While the IETF standardization process of the Mobile IPv6 and Network Mobility (NEMO) protocols is almost complete, their large-scale deployment is not yet possible. With these technologies, in order to hide location changes of the mobile nodes from the rest of the Internet, a specific router called a home agent is used. However, this equipment generates resilience and performance issues such as protocol scalability and longer paths. In order to solve these problems, we describe and analyze a new concept called Home Agent Migration. The main feature of this solution is the distribution of home agents inside the current Internet topology to reduce distances to end-nodes. As is usually done for anycast routing, they advertise the same network prefix from different locations; moreover they also exchange information about their associations with mobile nodes. This produces a Global Mobile eXchange (GMX), an overlay network that efficiently handles data traffic from and to mobile nodes, and operates home agents as would an Internet eXchange Point (IXP). When a correspondent node needs to exchange packets with a mobile node, the data traffic will be intercepted by its closest GMX home agent and redirected to the home agent to which the mobile node is bound.
By focusing on what can be observed by running traceroute-like measurements at a high frequency from a single monitor to a fixed destination set, we show that the observed view of the topology is constantly evolving at a pace much higher than expected. Repeated measurements discover new IP addresses at a constant rate, for long period of times (up to several months).In order to provide explanations, we study this phenomenon both at the IP, and at the Autonomous System levels. We show that this renewal of IP addresses is partially caused by a BGP routing dynamics, altering paths between existing ASes. Furthermore, we conjecture that an intra AS routing dynamics is another cause of this phenomenon.
Unlike other wireless technologies, the deployment of 802.11 networks is not limited to operators: access points can easily be installed by end-users for domestic use. This singular type of deployment is the reason why 802.11 networks are omnipresent in our urban landscapes. Indeed, in metropolitan areas, laptops frequently detect tens of 802.11 access points from the same location. In this work, we describe both simple and more complex data about access points obtained in two Paris districts during an extensive experiment from August to October 2007. We introduce a lightweight scanning platform that runs on common smartphones. Using the obtained data, we examine various parameters: (1) SSID, (2) manufacturers, (3) security modes, (4) density, (5) data rates, and (6) channels utilization. For example, we show that in the two districts that we mapped as few as 7% of the Wi-Fi networks are not secured. Similarly, we provide a practical evidence that 90% of detected access points where installed along with DSL Internet access.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.